Tympan clamp



Sept. 16, 1924, 1,508.951

A. F. BAKER TYMPAN CLAMP Filed June 1. 1923 I Irv/verifier: 6flzexanderli'fiai cer Patented Sept. 16, 1924.

resin ALEXANDER F. BAKER, OF QUINCY, MASSACHUSETTS.

TYMPAN CLAMP.

Application filed June 1,-

to a cylinder and in its more specific aspect it contemplates theprovision in a single structure of a combined tympan' clamp and sheetgripper.

My invention will be readily understood by reference to the followingdescription of an illustrative embodiment thereof shown by way ofexample in the accompanying drawings, wherein:

Fig. 1 is an elevation of a cylinder with one form of my improvedmechanism applied thereto and with parts broken away; and

Figs. 2, 3- and 4 are sections on like numbered lines of Fig. 1, Figs. 3and 4 being on an enlarged scale. I I

Referring to the drawings, I have there shown in Fig. 1 for the purposeof illustrating my invention an impression cylinder 5 trunnioned in theframe members 7 and 9. Referring to Fig. 2, the portion 11 of thecylinder is adapted to support the tympan or blanket 13, one end ofwhich, as shown on the upper sidein Fig. 2, may be clamped by theimproved form of clamp presently to be described and the other end ofwhich is secured by any known or suitable form of take-up mechanism 15.

Herein the end of the tympan 13 is clamped against the edge 17 of thesupporting surface 11 by means of a clamping bar 19 which may be movablysupported on two swingable radial arms 21 preferably centered at thecenter line of the cylinder 5 and conveniently located adjacent thebases of that cylinder, thev cross-bar 19 and thearms 21 forming a U,the legs of which may be braced by the cross web 23. Herein see Fig. 2)I have shown the arms as pivoted on hub-like studs 24 at the bases ofthe cylinder. v a

To swing the arms 21 so that the bar 19 is pressed in gripping relationagainst the 1923. Serial Ito/642,753.

abutment 17 I may utilize blade springs 25 secured to these arms andnormallyften sioned to press the arms to the right viewing Fig. 3 asthere illustrated in full lines. When it is desired to release thetympan the arms may be swung to the left to release the clampingpressure and for that purpose 1 preferably adopt such a construction asis herein shown and which I will next describe. The springs 25 may besecured to pins 27 eccentrlcally mounted on crank. discs 29 disposedadjacent the bases of the cylinder 5 and carried by a rock shaft 31extending lengthwise of the cylinder in the interior of the same. Pins33 on thecrank discs are adapted to make contact with stop pins 35 onthe bases of the cylinder 5. When the gripper is closed the pin 27 isnormally I somewhat below the line connecting the center of the shaft 31and the point of connection with arm 21 of the spring 25, thespring 25and the disc being in effect arms of a toggle which is slightly brokenpast dead center position so that the tension of the spring, withoutmaterially relaxing the clamping pressure thereof on the tympan clampingbar 19 tends still further to break the toggle and to rotate the disc 29clockwise viewing the figure, thus holding the pins 33 and 35 inengagement as shown. To relax the clamping pressure the shaft 31 may berotated, counterclockwise in the figure, and I have herein shown (seeFig. 3) flattened surfaces 37 thereon to facilitate the application'of awrench or the like. As the shaft 31 is turned the spring 25 is somewhatcompressed until the point 27 moves past dead center and then the toggleis free to break in the reverse direction, the disc 29 will rotatefreelyin a counterclockwise direction and the arms 21 may swing to thedotted line 39 adapted to cooperate with the circumferential surface ofthe bar 19. -To open and close these grippers at proper times they aremounted (see Fig. 4:) on reciprocating rods 41 guided in the bar 19 andthe cross web 23 and they are normally pressed to closed position bysprings 43 surrounding the rods andinterposed between the bar 19 andsuitable collars 45 carried by the rods.

The lower ends of the rods 41 may be connected to a cross member 4LT onwhich is mounted one or more cam follower rolls 49 adapted to cooperatewith cams on. av cam shaft 51 concentric with the impression cylinder 5.In the present embodiment of the invention the cam shaft 51 does notrotate and the rods are operated by the rotation of the cylinder 5carrying the follower rolls ll) around the cams. To permit the grippersto be operated at different times in the revolution of the cylinder 5 Imay provide for each follower a pair of edge cams 53 and 55 having nosesor rise portions relatively displaced circumferentially and adaptedalternatively to be brought into cooperation with the followers. Toeffect this the cams 53 and may be placed side by side on the shaftwhich may be shifted axially to bring one or another into cooperationwith a follower 49. In the drawings I have shown cams 53 as in operativeposition and it will be clearly understood from Fig. a that in therotation of the cylinder the cam will operate at intervals to lift therods ell simultaneously against the force of the springs 4L5, raisingthe gripper fingers 39 and opening the grippers for the reception orrelease of a sheet of paper. If the shaft 51 is shifted to the rightviewing Fig. 1 the cams 53 will be thrown out of action and the cams 55will be brought into line with the followers 49 so that they will act tolift the rods during the succeeding rotation of the cylinder and theopening of the grippers will take place at a different time due to therelative circumferential displacement of the rises on cams 53 and shownin F 3. To obviate drag and to facilitate the shifting of the shaft 51the cam followers 49 conveniently are supported free of. the lowerportions of the cams and make contact only with the rises of the same atthe time when the grippers are to be opened and for this purpose and toavoid undue strain on the gripper fingers 39 the cross-bar 457 whichcarries the followers may have connected thereto rods 57 guided in thecross web 23 and clamping bar 19 and adapted to receive stop pins 59which make contact with the upper surface of the former and stop thedownward movement of the gripper carrying rods 41 and their associatedmechanism under the action of the springs 45. The shaft 51 may beactuated in any desired manner and I have herein shown it extending tothe exterior of the cylinder (see Fig. 1) and having a squared portioncooperating with a yoke 61 on a pivoted lever 63, which lever may beswung at suitable intervals by cam 65 which is driven in any desiredmanner at proper times in the operation of the printing mechanism as a.whole. The cooperation of the yoke 63 with the squared portion of theshaft holds the latter against rotation and the shifting movement,taking place while the followers 1-9 are supported away from the cams asshown in Fig. 3, is readily effected.

It will be apparent that as the arms 21 swing about the center of thecylinder and the axis of revolution of the cam shaft 53 the tympan clampcan be moved freely from the full to the dotted line position of F 3when it is desired to release the tympan without disarranging thegripper operating mechanism.

I have described in detail the particular embodiment of my inventionshown by way of example in the accompanying drawings. Obviously theconstruction may be varied widely without departing from the inven tionand what I claim as new and desire to secure by Letters Patent I shallexpress in the following claims.

Claims:

1. A cylinder having a tympan clamp organized to swing about the centerof the cylinder, grippers carried by the clamp and a shaft disposedcentrally of the cylinder for operating the grippers.

2. A cylinder having a movable clamp for securing the tympan andgrippers carried by said clamp and movable therewith.

3. In combination with a cylinder radial arms, a bar carried thereby andserving as a tympan clamp, plungers in said bar having gripper lingersthereon and means disposed at the pivot of said arms for operating theplungers.

4%. In combination with a cylinder radial. arms, a bar carried therebyand serving as a tympan clamp, plungers in said bar having gripperfingers thereon and a central cam shaft for operating the plungers.

5. In combination with a cylinder a tynn pan clamp comprising a framemounted to swing about the center of the cylinder, grippers carried bythe frame and centrally disposed means for operating the same.

6. In combination with a cylinder a shiftable tympan clamp, gripperscarried thereby and shiftable therewith and means for operating thegrippers organized to permit them to 7' move freely with respect theretoin the shifting movement of the clamp.

7. In combination with a cylinder a tympan clamp, a. spring for pressingthe same to clamping position and a shiftable abutment supporting thespring whereby it may be moved bodily to release the tympan.

8. In combination with a cylinder a tympan clamp, a spring for pressingthe same to clamping position and a manually mov able eccentric mountingfor the spring.

9. In combination with a cylinder a swinging tympan clamp and a manuallyOperable toggle for operating the same.

10. In combination with a cylinder a swinging tympan clamp and a springactuated, manually operable toggle acting on said clamp.

11. In combination with a cylinder a swinging tympan clamp, a toggleconnected thereto resiliently tending to break, means limiting movementof said toggle in one direction whereby it holds said clamp closed andmanually operable means for reversely breaking the toggle.

12. In combination with a cylinder a tympan clamp comprising a pair ofradial arms and a clamping cross-bar, a shaft disposed parallel to saidcross-bar and adapted to be rocked manually, crank discs on the shaft,stop means at the bases of the: cylinder for said discs, springs securedto said clamp and cccentrically connected to said discs at points lyingbeyond dead center when said discs are restrainedby said stop means. I

13. In combination with a cylinder a swinging tympan clamp, a leafspring having one end secured thereto and a crank disc to which theother end of the spring is secured.

14:. In combination with a cylinder a tympan clamp comprising swingableradial arms and a cross-bar, a rock shaft, cranks thereon, springsbetween the cranks and said clamp and stop means for the shaft to holdsaid discs as abutments from which the springs act to press the clampinto engagement with the tympan.

15. In combination with a cylinder a swinging tympan clamp and a togglehaving a spring arm acting on the clamp and means limiting movementofthe toggle in one direction.

16. In combination with a cylinder a swinging tympan clamp and a togglehaving a spring arm acting on the clamp, means limiting movement of thetoggle in one clirection and a shaft providing means for swinging theother arm of the toggle in the other direction.

17. In combination with a cylinder a tympan clamp comprising a framemounted to swing about the center of the cylinder,

plungers in the frame having gripper fine gers and a central axiallyshiftable cam shaft having sets of cams for alternatively operating theplungers.

18. In combmation with a cylinder a tympan clamp comprising a framemounted to swing about the center of the cylinder,

tympan clamp comprising a frame mounted to swing about the center of thecylinder, plungers in the frame having gripper fingers, means foroperating the plungers comprising an axial non-rotating shaft and meansfor shifting the same axially.

20. In combination with a cylinder radially reciprocable plungerscarrying gripper fingers and a central axially shiftable shaft havingcams adapted to be brought selectively into cooperating relation withsaid plungers by shifting movement of the shaft.

21. In combination with a cylinder radially reciprocable plungerscarrying gripper fingers and a central axially shiftable shaft havingedge cams providing rises adapted to be brought selectively intocooperating relation with said plungers by shifting movement of theshaft, said plungers normally supported free of the lower portions ofsaid cams whereby to facilitate the shifting of the shaft.

22. In combination with a cylinder reciprocable plungers carryinggripper fingers and an axially shiftable shaft having cams adapted tooperate the plungers by the passage of the same over the cams in therotation of the cylinder, the shifting of the shaft serving to presentdifierent cams to the plungers.

In testimony whereof, I have signed my name to this specification.

ALEXANDER F. BAKER.

